Zhang Sheng, Echegoyen Luis
Department of Chemistry, Clemson University, Clemson, SC 29634, USA.
J Am Chem Soc. 2005 Feb 16;127(6):2006-11. doi: 10.1021/ja044411h.
A hydrogen-bond forming tris(amide) receptor based on cyclotriveratrylene (CTV) was prepared. Self-assembled monolayers (SAMs) of the receptor were formed on gold surfaces. Desorption experiments show a surface coverage of 2.26 x 10(-10) mol/cm(2). (1)H NMR and UV measurements confirm that the receptor exhibits the highest affinity for acetate ions among the anions studied. Electrochemical impedance was used to investigate anion sensing by the SAMs and proved to be an efficient and convenient technique for detecting anions in aqueous solutions. Upon binding acetate anions, the monolayer-modified gold electrodes show a drastic increase of the R(ct) values when Fe(CN)(6)(3-/4-) is used as the redox probe. When the probe was changed to a positively charged one, Ru(NH3)(6)(3+/2+), the R(ct) values decreased monotonically as the acetate concentration was increased, thus confirming the accumulation of negative surface charge upon anion binding. H(2)PO(4-) shows some interference when sensing AcO-. Other monovalent anions such as Cl-, Br-, NO3(-) and HSO4(-) do not bind to the CTV receptor either in solution or on the surfaces.
制备了一种基于环番（CTV）的形成氢键的三（酰胺）受体。该受体在金表面形成了自组装单分子层（SAMs）。解吸实验表明表面覆盖率为2.26×10⁻¹⁰ mol/cm²。¹H NMR和紫外测量证实，在所研究的阴离子中，该受体对醋酸根离子具有最高的亲和力。采用电化学阻抗法研究了SAMs对阴离子的传感作用，结果表明这是一种检测水溶液中阴离子的有效且便捷的技术。当以Fe(CN)₆³⁻/⁴⁻作为氧化还原探针时，结合醋酸根阴离子后，单分子层修饰的金电极的R(ct)值急剧增加。当将探针换成带正电荷的Ru(NH₃)₆³⁺/²⁺时，随着醋酸根浓度的增加，R(ct)值单调下降，从而证实了阴离子结合后表面负电荷的积累。在传感AcO⁻时，H₂PO₄⁻会产生一些干扰。其他一价阴离子如Cl⁻、Br⁻、NO₃⁻和HSO₄⁻在溶液中或表面均不与CTV受体结合。
